[Elecraft] K3 Setup Failing

[Ed]

What Don is saying is true.  My manual, page 58 shows the factory default as 4800 b.  Try resetting it to 38400 using the “config” menu.  
You will have to also do the same with your computer.  Then try reloading the software.  Anything you have saved with your present setup 
could be corrupted so you may have to start over.  38400 is what the K3 and it’s companions want to communicate with.  Also not
all RS232 to USB cables will work.  A lot of them have something missing in the chip they use.